Psalms 51:5

Behold, I was shapen in iniquity; and in sin did my mother conceive me.

Behold, I was shapen - Hebrew chowlaalªtiy (H2342); literally, brought forth amidst labour pains.

In iniquity. In Adam the whole human race fell, so that his sin was propagated by generation; for as the punishment affects all his race, even those who have not followed him in actual sin (Romans 5:12), as infants, so must his sin (Job 14:4). This is what is termed original or birth-sin-an hereditary taint, whereby from our birth we are inclined to evil. 'In every person born into this world, it deserveth God's wrath and damnation.' "Iniquity" х `aawown (H5771)] is always used of imputable guilty." Compare Genesis 5:3, contrasted with "Adam begat a son in his own likeness, after his image;" whereas "in the day that God created man, in the likeness of God made He him." Compare Genesis 8:21; Ephesians 2:3.

And in sin did my mother conceive me - not referring to the sin of his mother, but of himself, I had the germ of sin from my birth, and even from my very conception (Psalms 58:3.)